textproduct: Quad Cities

KEY MESSAGES

- Isolated-scattered showers/storms are expected through the afternoon, with a line of strong/severe storms set to come through this evening. Severe weather is possible, with a Slight Risk (level 2/5) for severe weather.

- A seasonally strong storm system will impact our area Friday afternoon and evening, where the SPC has highlighted much of our area in an Enhanced Risk (level 3/5) for severe weather.

- Much cooler airmass moves in this weekend behind a cold front, bringing unseasonally cool temperatures back to the area. Temperatures in the 30s through the nighttime hours will bring the potential for frost/freeze, especially in our north.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 126 PM CDT Wed Apr 15 2026

Seasonally strong shortwave trof currently located over central Nebraska will continue to track east through Iowa this afternoon/evening. A surface low pressure will pass southwest to northeast just northwest of our area, dragging a cold front through our area this evening/tonight. While we already have ongoing showers and storms, we are expecting another round of storms as the cold front moves through the area this evening/tonight. Ahead of that, we will have a stationary/warm front draped over the area, which will be another focus for convective initiation ahead of the main line of convection. This is currently located between the Highway 30 and Highway 34 corridors. Thus, a few rounds of storms are expected today, where flash flooding is possible. A Flood Watch remains for those areas at greatest risk, owing to heavy rainfall yesterday. The SPC has our whole area outlooked in a Slight Risk (level 2/5) for severe weather today, where our best chances for severe weather will be with the line of storms progged to come through with the cold front this evening. Isolated severe storms are possible ahead of this through the afternoon, but confidence is low on coverage and severity.

Looking at model soundings, we can expect another day of mixed-mode convection. Early-Mid afternoon, we are likely to continue to see scattered showers and storms. Given a lot of cloud cover and higher coverage of showers/storms in our north, the severe threat should remain relatively low into mid-afternoon. Although, areas south of Interstate 80 will have seen more sun peeking through, which has allowed more instability to build. Thus, there will be a little more of a severe threat in our south, generally in the form of semi- discrete supercells. Confidence is low on this at this time, but will further get monitored for the potential through mesoscale analysis this afternoon. This convection will generally be seen between the hours of 12-4 PM. Going into late afternoon and evening, we will see a line (possibly disconnected line of supercells) moving into our area from west to east, with some leading semi-discrete cells as well. The leading cells could be supercellular, which are currently looking to develop between the Highway 30 and Highway 34 corridors. These supercells may form just ahead of the line, generally between 4-6 PM, and then get absorbed into the main line. As we get towards the evening hours, the aforementioned line (QLCS- like with embedded supercells) will move through the area from west to east. Timing-Wise, this is expected to move into our west around 5-7 PM, and move out of our area by midnight local time. The best severe threat will be in the late afternoon/evening hours, but gradually decreasing after sunset.

Now a look into the environment in place. The AM convection and resultant cloud cover has delayed our surface heating a bit, but clearing skies have been seen. This may limit the overall instability, but will still be sufficient. We are still looking at the potential for CAPE around 2000-3000+, collocated with shear around 50-60+ KTs, with little/no cap seen in forecast soundings. Thus, we have the necessary CAPE/Shear balance to favor supercells today. Although, with strong forcing moving in this afternoon and evening, upscale growth is expected. As was mentioned, this could be in the form of a disconnected line with embedded supercells. Lapse rates are once again favorable for hail in the midlevels, collocated with a fat CAPE profile in the hail growth layer. SPC highlights parts of our area in the potential for significant hail (2"+), which is possible. Otherwise, all hazards are in play today, with the primary threat being winds and embedded tornadoes when the line of convection comes through this evening. We are especially focusing on counties along the Interstate 80 corridor, as this is generally where the stalled out boundary will be. This will serve as a focus point for severe weather (some significant severe weather possible), with the increased tornado threat.

Tonight and through Thursday, weak ridging moves in, with a surface high pressure quickly passing through. Thus, after any residual showers move out Thursday AM, we should remain dry for the remainder of the day. Clouds will also decrease through the day, with light winds and temperatures increasing into the mid-upper 70s. Thus, we are in for a beautiful day.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 126 PM CDT Wed Apr 15 2026

Friday will be another day of concern, as a potent shortwave tracks off of the Rockies and towards the Upper Midwest. This wave will develop a seasonally strong low pressure system, progged to drag a strong cold front through the area. Ahead of this, we will have an environment favorable for organized convection that can become strong to severe. Uncertainty remains with regards to timing, which can lead to impacts on the overall severe threat. Guidance has been hinting at this moving through Friday evening/night. Ahead of that, we will see a mix of clouds/sun, which will help build instability. According to model soundings, we may have CAPE values upwards to 2000-3000+, with shear around 35-45 KTs. The shear is a little lower than we have seen with the recent events, but sufficient for organized convection. Although, this would lead me to believe that we will largely be dealing with a line of strong/severe convection, but some initial isolated-scattered storms cannot be ruled out. More details are to come, as more short term hi-res CAMs start rolling in over the next 24-36 hours. The SPC has highlighted much of our area in an Enhanced Risk (level 3/5) for severe weather, with a Slight Risk (level 2/5) for areas east of the Mississippi River. Continue to monitor the forecast for future updates.

This weekend, upper level flow becomes northwesterly behind the aforementioned shortwave. Modest cold advection will kick in, bringing much cooler air to the area. Daytime temperatures are set to be in the upper 40s to 50s through the weekend, which is quite the change to the 70s and 80s we have been seeing. Overnight lows will be in the 30s, with areas north of Interstate 80 seeing lows approaching freezing. Thus, our north will have the chance to see a frost/freeze during this timeframe. Although, confidence is lower on this now, as temperatures have trended upwards a few degrees since the last forecast package. Dry conditions are expected through the weekend, with mostly clear skies. While cooler, it should be a relatively pleasant weekend.

Going into next week, it looks like the upper level pattern becomes active again. There remains many differences amongst guidance, but precipitation chances return to the area by midweek, along with increasing temperatures.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1238 PM CDT Wed Apr 15 2026

The main focus of this TAF issuance is on the shower and thunderstorm potential this afternoon and evening. The first wave of showers and a couple lightning strikes are lifting northeastward and are expected to pass out of the TAF sites in the next couple hours. Another line of storms is expected to develop around or after 22Z, then traverse the TAF sites through about 04Z. Tried to adjust the timing a bit with the latest guidance to start/end the storm potential from west to east. MVFR ceilings and visibilities are possible with any storm that develops with visibilities possibly dropping lower in heavier precipitation. Erratic wind gusts may exceed 35-30kts as the main line of storms passes through the TAF sites. Conditions will improve from west to east after overnight into Thursday morning.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Flood Watch until midnight CDT tonight for IAZ040>042-051>054. IL...Flood Watch until midnight CDT tonight for ILZ001-002-007. MO...None.